Coordination Mode Versatility and Intramolecular Bond Activation in Metal Complexes Supported by a Family of Tris(amidato)amine Ligands 公开

Jones, Matthew (2010)

Permanent URL: https://etd.library.emory.edu/concern/etds/sf268539b?locale=zh
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Abstract

Abstract
Coordination Mode Versatility and Intramolecular Bond Activation in Metal Complexes Supported by a Family of Tripodal Tris(amidato)amine Ligands
By Matthew B. Jones

In the first part of this dissertation, the synthesis and coordination chemistry of a tris(amidato)amine ligand scaffold is discussed. The amidate acyl substituents can act as regulatory elements to control access to the open coordination site on metal complexes of the ligand. This control is found to have both a steric and electrostatic component, depending on the identity of the acyl substituent. Variation of these acyl substituents can have an effect on both the coordination number and primary coordination sphere of the resultant complexes. The ambidentate nature of the amidate substituents makes this ligand scaffold applicable for binding a variety of metal ions (Co, Ni, Al). The synthetic, spectral, and structural details of a variety of metal complexes supported by these ligands are discussed, and the ability of some of these complexes to bind exogenous anions is detailed.

The second part of this work describes the reactivity of cobalt and iron complex of these ligands towards intramolecular bond activation. It is found that C-H bonds in the ligand acyl substituents can act as traps for high-valent metal-based oxidants. While the cobalt reaction can only be accomplished with the help of a strong oxidant, the C-H bond activation with iron is found to proceed with dioxygen, as confirmed by labeling studies. The similarity between the reactions using the differing oxidants implies that the C-H activation likely proceeds via some Fe-oxo adduct in both cases. When the acyl substituents of the ligands are replaced with perfluoroaryl groups, the iron complex is shown to activate intramolecular C-F bonds instead. This reaction is also shown to proceed in the presence of dioxygen as the terminal oxidant/O-atom source.

Table of Contents

Table of Contents

Part I. Introduction...1

Chapter 1 : Bioinspired Ligand Design for Promoting New Modes of Base Metal Reactivity...1

Section 1-1. Bioinorganic Chemistry...1
Section 1-2. Iron in Base Metal Catalysis...5
Section 1-3. Amidate Ligands in Nature and in Synthetic Complexes...11
Section 1-4. Tripodal, Tetradentate Ligands...17
Section 1-5. Ligand Design...20
Section 1-6. Overview of this Dissertation...22

Part II. Coordination Chemistry of Metal Complexes Supported by a Tris(amidato)amine Ligand Scaffold...24

Chapter 2 : Tripodal Phenylamine-based Ligands and Their Cobalt(II) Complexes...24

Section 2-1. Introduction...24
Section 2-2. Results and Discussion...28
Section 2-3. Experimental...53

Chapter 3: Chelating Tris(amidate) Ligands: Versatile Scaffolds for Nickel(II)...67

Section 3-1. Introduction...67
Section 3-2. Results and Discussion...72
Section 3-3. Experimental...99

Chapter 4: Synthetic, Spectral, and Structural Studies of Mononuclear Tris(κ2-amidate) Aluminum Complexes Supported by Tripodal Ligands...109

Section 4-1. Introduction...109
Section 4-2. Results and Discussion...115
Section 4-3. Experimental...124

Part III. Intramolecular Bond Activation by Cobalt and Iron Complexes Supported by a Tris(amidato)amine Ligand Scaffold...129

Chapter 5: The Intramolecular Activation of C-H Bonds by Cobalt and Iron Complexes Supported by a Trianionic, Tripodal Ligand...129

Section 5-1. Introduction...129
Section 5-2. Results and Discussion...138
Section 5-3. Experimental...162

Chapter 6: Facile C-F Bond Activation by Fe(II) Complexes Using Dioxygen as Terminal Oxidant and Oxygen Atom Source...171

Section 6-1. Introduction...171
Section 6-2. Results and Discussion...176
Section 6-3. Experimental...202

References...211

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